Current FDA regulations essentially preclude the use of PCR polyolefin plastic materials for direct contact with food and beverages in containers unless stringent purity requirements are met. While there is a need to provide non-food and beverage containers made entirely of PCR polyolefin plastic materials, past attempts have met with only limited success and marketplace acceptance due to problems with container color, presence of unwanted fragrances, cross contamination, and complexity of the process.
Colored PCR polyolefin plastics are often imparted with strong fragrances due to residual volatiles that have been absorbed in the plastic from detergents, fabric softeners, shampoos, beauty care products, and other products they contained. Branded products companies have resisted putting their products in direct contact with PCR polyolefin plastics in the belief that it would change how such products were perceived by consumers if they were presented with an unfamiliar fragrance. Thus there is a current need for containers produced from 100% colored polyolefin PCR that have the conventional physical properties desired in plastic containers for fabric care, household, hair care, skin care, and other beauty care products, and are fragrance-free.
To provide desirable PCR polyolefin materials, the present invention provides certain improvements to the process disclosed in U.S. Pat. No. 5,767,230 issued Jun. 16, 1998 to Ecoplast Corporation, the assignee of the present application. In brief, the Ecoplast Patent discloses a process and apparatus for use in removing certain undesirable contaminations from post consumer recyclable (PCR) container fragments to form a desirable feedstock for further processing into PCR products, such as described, supra. The process patented involves the devolitization of flakes, or chips, of a predetermined size in heated stirred bed and fluidized bed vessels for a predetermined time period to produce flakes low or free of volatiles and fragrances to be used for food contact.
While the patented process functions satisfactorily for its intended purpose, it possesses certain limitations. For instance, the size of the flakes fed into the vessel must be controlled accurately. And, the vessel and stirrer geometries need to be closely related to the flake size to ensure proper flow of heated gas and flow of flakes through the vessel to ensure complete de-volatization. Typically, the de-volatized flakes are then transferred to storage silos to await delivery to users who employ PCR polyolefin products for certain applications, such as extrusion and blow molding, which have a big risk of cross contamination and high material handling cost.
An important object of the present invention is to provide a process which tolerates greater latitude in the source material of the raw flakes, in their processing parameters, and in the de-volatization vessel geometries, to thereby provide PCR polyolefin materials that have desirable properties for subsequent use in food containers, household, and personal care product applications.